Abstract
Introduction
Pedicle screw-based dynamic implants are considered to be a possibility to obtain stability and at the same time reduce the risk of the development of adjacent segment disease (ASD) in the lumbar spine.
The aim of this study was to compare hybrid constructs (TLIF + adjacent dynamic stabilization) with rigid fusions (TLIF) in the lumbar spine, regarding clinical outcome, adjacent segment disease, and possible complications.
Materials and Methods
Between June 2008 and April 2010, a total of 104 patients underwent either 2-level hybrid surgery (TLIF + adjacent dynamic stabilization) (51 patients) or 2-level fusion (TLIF) (53 patients) in the lumbar spine for lumbar spinal stenosis with or without mild instability.
Preoperatively, no significant differences regarding demographic factors, diagnosis or baseline outcome parameters could be found between the groups.
To assess clinical outcome, SF36, Oswestry, and VAS pain scores were obtained preoperatively at last follow-up. Any revision surgery for symptomatic adjacent level degeneration and for complications was recorded.
Mean follow-up was 27 months.
Results
Clinical outcome Clinical outcome parameters showed significant improvement from baseline after surgery in both groups; the difference of improvement between the two groups was statistically not significant.
Adjacent segment disease In the fusion-group, the revision rate because of ASD was 7.5% compared with 5.9% in the dynamic-group. Fisher exact test showed no statistical difference in the ASD-related revision rates between both groups (p = 0.513)
Mean time until revision surgery was 15.8 months in the fusion-group and 24.3 months in the dynamic group.
Complications Fusion Group: Apart from revisions due to ASD, two patients had to undergo revision surgery (1 x infection, 1 x further decompression). No failure of the hardware was noticed in the fusion-group.
In the dynamic group, apart from revisions due to ASD, one patient had to undergo revision surgery due to screw-loosening after 15 months. Furthermore, one of the patients with ASD in the dynamic group had an additional loosening of the dynamic part of the rod. Another patient showed a broken dynamic rod at 12 months follow-up. Due to lack of symptoms he did not undergo revision surgery up to now.
All together the implant failure rate in the dynamic group was 5.9%
Conclusion
At a mean follow-up of 27 months, clinical outcomes and ASD-related revision rates of 2-level TLIF and 2-level hybrid fusions with adjacent dynamic stabilization seem to be very comparable.
There was a trend towards earlier revisions in the fusion group, but at the same time a trend towards a higher implant-failure rate could be observed in the dynamic group.
Yes
None declared